Binomial Expansion

Question 1

Formula for binomial coefficient?
(nC r)

Answer 1

n! / r!(n-r)!

Question 2

Binomial expansion formula for values greater than 1?

Answer 2

(a + bx)^n = a^n + nCr • a^(n-r) • b^r

Question 3

Binomial expansion formula for values less than 1?

Answer 3

(a + bx)^n =
a^n[1 + nx + n(n-1)…/r! • (bx/a)^r]
Valid for |x| less than 1 or |bx/a|